A growing collection of articles on software development, system design (HLD & LLD), and practical coding tips. I focus on making complex ideas simple, so developers can learn faster and build better.
The Problem: When the Same Payment Is Processed Twice Imagine a customer purchases a product worth $100 from an e-commerce application. After the customer completes the payment, the payment gateway su
Imagine we need to refund $50 to a group of customers. We have their customer IDs: const customerIds = ["C101", "C102", "C103", "C104"]; For each customer, we need to update their account and add th
In the previous article, we explored how the Two-Phase Commit (2PC) protocol enables multiple services to either commit or rollback a distributed transaction together. We introduced the roles of the C
Most developers are familiar with database transactions. A database transaction guarantees that either all operations succeed together or all operations fail together. For example, here's a money tran
In today's article we will discuss about why failing services can crash your entire system and what we can do to prevent it. First, What is considered failing service? A service does not need to compl
In previous article , we discussed lost updates and database locking, which focused on how data is written. In this article, we’ll focus on how data is read during a transaction using isolation levels
Hello, today i am going to deep dive into optimistic and pessimistic locking from a database perspective. First, let's look at the following example: DO $$ DECLARE current_stock INT; BEGIN SEL
In this article, I will explain how Python behaves, particularly the Global Interpreter Lock (GIL). First, let's look at the following example: import threading import time NUM_THREADS = 4 N = 2000
In this article, I will explain the Strategy Design Pattern in a simple and efficient way. First, let’s look at the code below: class PaymentService { public void pay(String type) { if (ty